Semiconductor devices are commonly found in modern electronic products. Semiconductor devices perform a wide range of functions such as signal processing, high-speed calculations, transmitting and receiving electromagnetic signals, controlling electronic devices, photoelectric generation, and creating visual images for television displays. Semiconductor devices are found in the fields of communications, power conversion, networks, computers, entertainment, and consumer products. Semiconductor devices are also found in military applications, aviation, automotive, industrial controllers, and office equipment.
Semiconductor packages are being made smaller and smaller to satisfy consumer demand for smaller end products. Making semiconductor packages with a thinner profile requires using thinner semiconductor die within the packages. However, for packaging types that are made using reconstituted (recon) wafers, thin die make the recon wafers flexible. A reconstituted wafer is formed by spreading semiconductor die out on a carrier and then depositing encapsulant to reconnect the die physically. The encapsulated die appear similarly to an unsingulated semiconductor wafer, but have been reconstituted into new wafer connected by encapsulant. Conductive layers, referred to as redistribution layers, are formed over the semiconductor die and encapsulant for electrical interconnect. The recon wafer tends to warp when forming redistribution layers (RDL), or otherwise processing the recon wafer, if the semiconductor die are thin.
Thick die are commonly used in the recon wafer to reduce warpage when forming RDL. The reconstituted wafer is backgrinded after forming the RDL to reduce a thickness of the die, and package as a whole. Both the semiconductor die and encapsulant are grinded, which thins the semiconductor die down to a desired thickness. However, the semiconductor die is exposed from the package in the process, which could result in contamination of the die due to backgrinding the semiconductor material at the same time as other materials. In addition, the backgrinding may degrade the strength of the semiconductor material.
Therefore, a need exists for a recon wafer process using thin semiconductor die that can control warpage.